The 1.5SMC27AHE3/57T is a Zener-type TVS from Vishay's 1.5SMC series, qualified to AEC-Q101 for automotive use. With a minimum breakdown voltage of 25.7V, the device triggers well before the clamp level, protecting downstream electronics from inductive load dumps or alternator field decay events common in automotive power distribution.
Package, temperature, and board-fit
The wide temperature span covers under-hood and cabin environments where thermal cycling is a given. The part is a single unidirectional channel — one TVS per package. There is no power line protection feature; it is designed for signal or low-power rail clamping rather than mains-level AC protection.